DE2041395A1 - Photosensitive copying paste for the production of screen printing forms - Google Patents

Description

K 1969 PP-Dr.N.-ur 14 August 1970

Description for registering the

KALLE AKTIENGESELLSCHAFT Wiesbaden-Biebrich

for a patent

Photosensitive copying paste for the production of screen printing forms

The invention relates to a photosensitive copier -

mass for the production of screen printing forms, which is a condensation product of an aromatic diazonium compound and contains a hydrophilic curable binder.

209809/08 71

ORIGINAL INSPECTED

- ρ _

The use of condensation products from aromatic diazonium compounds, ζ. B. Diazodiphenylamines, and aldehydes for screen printing is e.g. B. from DAS 1 289 741 known. It is also known that monomeric diazo compounds, ζ. Β. Diazodiphenylamines, in combination with aldehydes, preferably layers suitable for screen printing result, which also crosslink during exposure (DBP 1 206 308).

In the German patent applications P 20 24 244.8 (United States Patent Application Ser. No. 826 297) and P 20 24 242.6 (United States Patent Application Ser. No. 826 296) are among others has been proposed, screen printing layers of curable binders and mixed condensation products of aromatic To produce diazonium compounds with condensable compounds and active carbonyl compounds. The condensation products are in the form of their water-soluble salts, e.g. B. the chlorides used. In the earlier patent applications mentioned, the salts of the condensation products with aliphatic Sulphonic acids are generally described as light-sensitive substances without any special properties or suitability for a particular purpose is indicated.

209809/0871

The object of the invention was to provide a photosensitive copying paste for the production of screen printing forms to propose, which has a high photosensitivity and good shelf life, and the copy layers which can be developed with aqueous solutions, preferably with pure water.

According to the invention, such a copying compound is proposed which contains a condensation product of an aromatic diazonium compound and a hydrophilic, hardenable binder and which is characterized in that it contains a condensation product of at least one unit each of the general types A (-D) _n and B, which are mutually by double-bonded bridge members which are derived from a condensate carbonyl compound, in which

A is the value of a compound containing at least two iso- or heterocyclic aromatic Contains rings and those in acidic medium in at least one place of the molecule with active Carbony! compound is condensable,

2 0 9809/0871

D is a diazonium salt group which is on an aromatic carbon atom of A,

η is an integer from 1-10 and

B is the remainder of a compound free of diazo groups is which in acidic medium to condense at least one point of their molecule with active carbonyl compound able to

wherein the anion of the diazonium salt is derived from an aliphatic monosulfonic acid with 1 to 6 carbon atoms.

The copying compounds according to the invention are more similar to the compounds known for the same purpose Art is characterized by a significantly higher sensitivity to light and shelf life. The higher sensitivity to light is essentially a property common to all mixed diazo condensates as described in the above mentioned earlier patent applications are described, regardless of their anion, while the shelf life and water solubility are essentially determined by the anion.

209809/0871

In the known screen printing layers, in order to ensure aqueous developability, mainly water-soluble diazonium salts, such as halides, and sulfates, especially chlorides, are used. It was found, however, that the copying compounds and screen printing layers produced with these diazonium salts only have a relatively short shelf life. ^

In practice, therefore, the photosensitive Substances as so-called sensitizers and the rest of the liquid copy paste as a so-called screen printing emulsion stored separately and only immediately before use, d. H. before coating the Screen printing carrier, combined to form the so-called screen printing varnish. One knew diazonium salts with better Can be stored in light-sensitive layers, but these salts were always suitable for aqueous development not enough water-soluble. From this fact of experience it was even assumed that water solubility and storability of diazonium salts were opposed to one another Properties are.

It was therefore particularly surprising that the invention used diazonium salts of lower aliphatic Sulfonic acids have a much longer shelf life

209809/0871

than the previously used water-soluble salts, both in solid form and in aqueous solution and in the final photosensitive layer, although the water solubility of their preferred Representative even surpasses that of the corresponding chlorides.

The diazonium salts according to the invention have compared to the homocondensation products used hitherto the further advantage that they can easily be obtained in solid form from the condensation mixtures obtained during manufacture let out.

In the case of the copying compositions according to the invention, it is possible to use them as ready-made screen printing varnishes in liquid form or can also be stored for months as presensitized screen printing materials.

The aliphatic monosulfonic acids, which are the anions of the Form diazonium condensates used according to the invention, generally have 1 to 6 carbon atoms and can optionally not too heavy substituents, e.g. B.

209809/0871

Halogen atoms, such as fluorine, chlorine, bromine or iodine, hydroxyl groups, Ether groups and the like. Contain. Generally there will be no more than one substituent. The aliphatic marriage Chain can be straight or branched or ring-shaped. It can also contain double bonds.

Examples of suitable sulfonic acids are methanesulfonic acid, ethanesulfonic acid, propane-2-sulfonic acid, propane-1-sulfonic acid, Butane-1-sulphonic acid, 3-methyl-butane-isulphonic acid, Cyclohexanesulfonic acid, hexane-1-sulfonic acid, Vinyl sulfonic acid, propene-1-sulfonic acid, 2-hydroxy-ethane-1-sulfonic acid, 3-hydroxy-propane-1-sulfonic acid, 3-methoxypropane-1-sulfonic acid, 2-chloroethanesulphonic acid, 2-bromoethanesulphonic acid, chloromethanesulphonic acid, etc.

Mixtures of salts of two or more ™ of these acids can be used.

Usually the salts of sulfonic acids with more less preferred than four carbon atoms, since their water solubility is already limited. It goes without saying that the chemical nature and the molecular weight are also included here of the condensation product, which also influence the water solubility. So

2 0 9809/0871

can relatively low molecular weight condensates containing hydrophilic groups, even in the Form of the hexanesulfonates have a satisfactory water solubility. In general, however, the lower Sulphonates and of these especially the methanesulphonates are preferred. The latter show the best water solubility and at the same time a good shelf life.

Another advantage of methanesulfonates over the higher sulfonates is their lower price. You let Finally, it is particularly easy to produce, since methanesulfonic acid is used for the production of mixed diazo condensates is a suitable condensation medium. When they are used, the condensate falls directly as methanesulf onat.

However, the mixed condensates can also be used as a condensation medium by condensation in other acids, e.g. Am Phosphoric acid, and can contain even smaller amounts of the condensation medium without disadvantage. In favorable cases, this even increases the shelf life. An excess of precipitant, e.g. B. sodium methanesulfonate, can in the invented

209809/0871

diazonium salt used as intended be included, without its effect - apart from the dilution - is impaired.

The production of the diazo polycondensates used according to the invention is in detail in the patent applications P 20 24 244.8 and P 20 24 242.6 (USA patent applications Ser. No. 826 297 and 826 296).

The condensation products can be produced by at least one aromatic diazonium compound of the general formula A (-D) and at least one Compound B, where the symbols have the meanings given above, with at least one active carbonyl compound, preferably formaldehyde, in free form or with agents that release such carbonyl compounds condensed in a strongly acidic medium.

Another process for the production of mixed diazonium condensates of the general type listed above consists in being more active on the application Carbonyl compound as such in the mixed condensation

2 0 9809/0871

- ίο -

dispensed with and instead of component B a modified second component B. of the general formula

E (-CHH _a - O -

used where

E a by splitting off m Η atoms from a compound B of the meaning given above resulting remainder,

R H, an aryl, alkyl or heterocyclic radical, preferably hydrogen,

Rk H, an alkyl or acyl radical with 1-4 C atoms

or a phenyl radical and preferably hydrogen, methyl, ethyl or acetyl and

m is a positive integer from 1 to about 10.

The condensation is carried out in the presence of a strongly acidic condensing agent. Used preferably concentrated, moderately strong to strong acids,

Particularly suitable condensing agents are phosphoric acid, methanesulfonic acid and sulfuric acid, which are in Concentrations of at least 40, preferably 70

ORIGINAL INSPECTED

- li -

up to 100% by weight can be used. the rest is generally water, but can also be wholly or partly from solvents, eg. B. methanol, acetic acid, N-methylpyrrolidone and the like. Good results are obtained, for example, if one uses 80-100 pounds of phosphoric acid, 80% sulfuric acid and 90% methanesulphonic acid used.

85 % phosphoric acid is a fairly mild condensing agent in which condensation can be carried out in a very gentle way. It is therefore the most preferred condensing agent, especially when using the second method, for all combinations of compounds that react quickly enough under these fairly mild conditions. 90 % methanesulfonic acid is a stronger agent. This acid has the further great advantage that it can dissolve a large number of components B and B.

The average molecular weights of the condensation products can, depending on the choice of condensation participants and conditions can be varied widely. It has, however has shown that mixed condensates with molecular weights are preferred for the production of good copier materials

209809/0871

between about 500 and 10,000 are suitable. It is of course to be noted here that it is here are mean values.

The following groups can be mentioned which cause the condensability of components A (-D) and B:

1. Aryl radicals and heterocyclic radicals which have core positions capable of condensation. Those residues in which these core positions are still activated are preferred. This activation can e.g. B. carried out by annealing with other aromatic rings or by substitution by groups such as -OH, -O-alkyl, -O-aryl, -SH, -S-alkyl, -S-aryl, -alkyl, -aryl, -amino, -Alkylamino, -Dialkylamino, -Arylamino, -Diarylamino etc. In addition to these activating substituents, in the condensable aromatic or heterocyclic radicals, radicals which hinder condensation, e.g. B. nitro or sulfonic acid groups occur when the activation caused by other residues is only reduced, but not canceled.

2. Residues that are themselves accessible to condensation and directly to iso- or heterocyclic radicals or to aliphatic radicals can be bound or the possibly

209809/0871

BATH ORIGINAL

are directly linked to each other. Belong here Groups such as carboxamide, sulfonic acid amide, N-alkyl sulfonic acid amide, N-ary-sulfonic acid amide, nitrile, Urea, thiourea, urethane, ureido, thioureido, glyoxaldiurein, imidazolone, guanidine, dicyandiamide and amino groups directly on aromatic rings.

An important group of diazonium compounds which are used as starting material for in the context of this invention Particularly preferred condensation products come into consideration is built up according to the following general formula

(R ₁ - R ₃ -) p R ₂ - N ₂ X

In this formula:

ρ is a positive integer from 1 to about 3 *, preferably 1.

X is the anion of the diazonium compound.

Usually an iso- or heterocyclic one which is optionally still substituted aromatic radical which has at least one condensable position, preferably an optionally substituted phenyl radical. Preferred substituents are those which have the Increase the reactivity of the core for condensation, especially alkyl and alkoxy groups.

209809/0871

Rp an aromatic ring of benzene or Naphthalene series, preferably a benzene ring, which apart from the diazo group still has other Can carry substituents.

R, a link between the rings R ^ and Rp, z. B. of the following types, where always the remainder R. on the left and the group R-zu on the right thinking is if R, is not symmetric:

simple homopolar bond

- (CH ₂ ) -NR ₁ J- (q = integer from 0 to 5, R ₁₁ = H,

Alkyl with 1-5 carbon atoms, aralkyl with 7-12 carbon atoms or aryl with 6-12 carbon atoms)

- (CH ₂ ) -NR _1J - (CH ₂ ) _r -NR ₅ - (r = integer from 2-5, R ₅ = H or

Alkyl with 1-5 carbon atoms)

0-R -NR ₁ , - 0- S- CO-NR ₁ , - so ₂

(R ₆ = arylene with 6-12 carbon atoms) '

209809/0871

Preferably, R is a homeopolar bond or one the links -0-, -S- and -NH-.

A particularly important group of diazo compounds, which according to the general formula R * - R, - Rp * "NpX are built up and which are preferably used for the preparation of the diazo condensation products are

Salts of diphenylamine-JJ-diazonium ion and its ^

Substitution products.

Preference is given especially diphenylamine ¹ J-diazonium salts, with 1-3 carbon atoms derived from the 3-alkoxy-ty-amino-diphenyläminen in the alkoxy group, in particular from ^3-methoxy-i l-amino-diphenylamine.

The compounds to be used as components B or as components B _{1 derived therefrom can}

z. B. belong to the following groups of substances:

Aromatic hydrocarbons ^L.

Aromatic amines'

Phenols and thiophenols

Phenol ethers and thiophenol ethers,

Heterocyclic compounds ^; ^ ■■? - ν

209809/0871

BATH ORIGINAL

Urea, thiourea, carboxamides

(aliphatic and aromatic) sulfonic acid amides (aliphatic and aromatic)

Components B and / or B., their Molecular weight less than 500, preferably less than 250, is.

Preferred compounds are phenol ethers, thiophenol ethers, aromatic hydrocarbons and non-basic heterocycles. Of these substance classes, those representatives are particularly advantageous which are derived from the diphenyl ether, Derive diphenyl sulfide, diphenyl methane and diphenyl and one or two substituents, e.g. B. halogen atoms, alkyl and alkoxy radicals, but preferably are unsubstituted.

A group of diazopolycondensates particularly preferred for use in the context of this invention are condensation products of 3-alkoxydiphenylamine- ⁱ J-diazonium salts, especially 3 ^{-methoxydiphenylamine- l} J-diazonium salts, and the above-mentioned second components, in particular those consisting of A (-D) and B ₁ under mild conditions, ie in 80 - 100%

209809/0871

Orthophosphoric acid were produced at temperatures from + IO to about 40 ° C. * Marks of such Condensates are good photosensitivity with good storage stability. As particularly preferred condensation products from this group there may be mentioned condensates of J-methoxy-diphenylamine-JJ-diazonium salt and components B * from the series

k, 4'-bis-methoxymethy1 diphenyl ether-4,4'-bis-methoxymethyl-diphenyl ¹ I, ¹ 1-diphenylmethane I'-bis-methoxymethyl and 4,4'-bis-methoxymethyl-diphenyl.

In particular, mixed condensates are used in the context of this invention which _{contain 0.1-5, preferably 0.5-2, even more preferably approximately 1 mole of B or B 1} per mole of A (-D) _n in mixed-condensed form.

For the preparation of the salts to be used according to the invention Organic sulfonic acids are generally added in concentrated form Solutions of a soluble salt of one of the mixed diazo condensates the acid that the anion is supposed to put in

209800/0871

free form or in the form of a soluble salt, the addition being made in solid substance or as a solution. The medium in which the production takes place should be such that it either contains the desired salt the aliphatic monosulfonic acid dissolves as little as possible or salting out by adding an excess of the Sulfonic acid or its salt allowed.

It is advantageous to work in an aqueous solution, i. H. one solves z. B. crude condensation mixtures, as in the Production of the condensation products accumulate in water and adds the corresponding sulfonic acid or their alkali salt in bulk or as a concentrated aqueous solution. The desired salt separates Depending on the partners used, in the form of a solid precipitate that can be suctioned off or as a tough one Mass from which is separated from the mother liquor by decanting.

However, it is also possible to use aliphatic sulfonic acids as condensation agents for the production of such condensates to be used and for the separation of the

209809/0871

wanted product with a nonsolvent for that To mix condensation product, which however dissolves the condensation medium.

It is favorable if the diazonium salt of an aliphatic monosulfonic acid used in the context of this invention also contains small amounts of acid, preferably H ₅ PO ^, H ₂ SO ^ or methanesulfonic acid, since this has a favorable effect on the shelf life of the product.

It is particularly easy if this amount of acid comes from the condensation agent, in which it does not is completely separated. But it can also be added to the pure substance afterwards. The amount of acid should generally not be more than 2 moles, preferably not more than 0.5 moles of acid per equivalent Diazonium groups.

Various hydrophilic binders can be used in combination for the production of the copying compounds according to the invention can be used with the described diazo compounds. Polyvinyl alcohol is very suitable, in some cases

2 09809/0871

acylated polyvinyl alcohol, partially hydrolyzed polyvinyl acetate, polyacrylic acid, methyl cellulose, Hydroxymethyl cellulose and gelatin. The synthetic colloids, e.g. B. polyvinyl alcohol, partially saponified Polyvinyl ester and by copolymerization ζ. Β. Internally plasticized polyvinyl acetate dispersions with maleatates are particularly cheap.

You can also add fillers in finely divided dispersed form to the copying materials, for. B. in grain sizes of 5 - 30 / u, preferably 10 - 20 ^ _u . Suitable fillers are plastics such as polyamides, polyesters, polyurethanes and vinyl polymers, eg. B. polyvinyl acetates, polystyrene, polyvinyl chlorides and polyvinylidene chlorides. Their use in the form of dispersions is preferred. Finely divided silicon dioxide, aluminum oxide, titanium dioxide, silica, clay, glass powder, metal complex dyes, color pigments can also be used as fillers. It is also possible to add plasticizers, wetting agents, starch, salts and preservatives.

209809/0871

The preferred solvent used for the liquid copying paste is water. A smaller proportion of the However, the solvent can also consist of water-miscible organic solvents, e.g. B. lower Alcohols, of which methanol is preferred.

In addition to pigment dyes, the copy paste can also be colored by dissolved dyes. In In some cases it is also useful to apply the non-colored copy paste after exposure and Development on the substrate, usually colored with a screen printing fabric. This can be done through Dip or pour a dye solution over them and rinsing off the unadsorbed excess dye. It is also possible, by dipping or pouring the alkaline solution of a coupling

component to form a dye in the crosslinked layer after development, as despite sufficient Light networking still undecomposed, capable of being coupled Diazo groups are present in the layer.

0 9809/0 «? 1

When the photosensitive copying compositions according to the invention are used as solid copying layers on a screen printing support are present, the materials known for screen printing can serve as a carrier. Come first and foremost the flat and round stencils for screen printing and textile printing in question. These can consist of tissues or Nonwovens or perforated plastic foils, such as polyamide or polyester, or made of silk fabric or Japanese paper, made of metal fabrics made of steel, brass or Bronze or from electroplated rotary stencils, preferably made of nickel.

The photosensitive compounds used in the copying compositions according to the invention also permit the addition of relatively large amounts of non-water-soluble resins and other substances with undiminished ease and speed Developability with aqueous developer.

The copying paste according to the invention in the form of presensitized screen printing material achieves the good properties the long-known bichromate colloid layers without their disadvantages. The one in it

2.09: 800/047

Diazo compounds used not only have good water solubility and shelf life, but are in In contrast to the previously common liquid or oily ones. Diazo condensation solid powders. For better They can be made up with other powdery water-soluble substances, e.g. B. polyvinyl alcohol, be mixed.

Above all, the new copying compounds and the copying materials produced with them are characterized by that they are significantly more light-sensitive compared to the diazo-based materials previously used for the same purpose and achieve the light sensitivity of comparable bichromate layers. You own on the other hand not the disadvantages of the bichromate copying materials, of which the material coated due to the thermal dark curing has a very low shelf life, the The short shelf life of the sensitized solution, the non-constancy of the copying properties and the toxicity of bichromats are best known.

Another disadvantage of the bichromate layers is the very difficult or mostly impossible stripping hardened layers. The detachability is often

209809/0871

- 21 -

required for economic reasons. The layers according to the invention, on the other hand, are distinguished by the fact that that despite excellent z. B. the pressure loads completely sufficient light crosslinking and even after additional z. B. thermal post-curing are much easier to decoat than bichromate layers. Even on rotary nickel stencils for which, according to DOS 1 522 526, bichromate layers are additionally post-hardened must be, keep the inventive copying materials without additional post-polymerization not only withstand high pressure loads, but can also be used according to the special issue 10 "film printing stencils" in BAYER Farben Revue, page 75 »desize with formic acid.

The composition of the copying layers obtained from the copying compositions according to the invention can vary within wide limits. By adding hardenable resins and binders, the proportion of photosensitive substance in the layer can be reduced and thus the photosensitivity can be increased. For screen printing layers, the proportion of diazo condensate should generally not be less than 2 % ; with 5 % it is already achieved that the exposed

20 9809/0871

Layer becomes completely water-insoluble, so that in most cases it is not necessary to use a concentration significantly higher than 5%. Of course, in certain cases, e.g. B. in the case of diazo condensates with a high proportion of second component B or B. or in the case of binders that are less easily crosslinkable, significantly larger proportions of diazo condensate can also be used. In general, however, this proportion is not higher than 50 %, preferably below 20 %.

For layers for screen printing with solvent inks, e.g. B-. commercial screen printing inks for printing of polyvinyl chloride surfaces, the layer only needs to consist of diazo condensate and colloid. Of the However, the addition of non-water-soluble fillers is advantageous for the mechanical properties.

Should the screen printing layer for predominantly water-based colors z. B. be used in textile printing, it is recommended to avoid or suppress a gradual Swelling an addition of substances that do not swell in water,

209809/0871

For such purposes, preference is given to using polyvinyl acetates, in particular in the form of aqueous dispersions. The proportion of polyvinyl acetate must generally not exceed 60-70% of the total solids content, so that the aqueous developability is retained.

Aqueous liquids are practically always used as developers. Preferably even with pure Water developed without any additives.

The following examples illustrate the invention but are not intended to limit its scope. Percentages are, unless otherwise noted, percentages by weight.

example 1

To dissolve 32.3 g of 3-methoxydiphenylamine-4-diazonium sulfate in 70.7 ml of 86% phosphoric acid , 12.9 g of M.lt'-bis-methoxymethyl-diphenyl ether were added dropwise with stirring. After 20 hours of condensation at 40 ° C. , the mixture was dissolved in 330 ml of water, and 2M0 ml of a chloride-free aqueous solution of sodium methanesulfonate containing 1 ½ g of this salt were added. The precipitation was after decanting the

209809/0871

Mother liquor redissolved in water and precipitated again in the same way, separated off, over in vacuo Dried phosphorus pentoxide and grinded to a powder.

Yield: 37 g (C 48.0 %, N 6.8 %, S 10.7 %, P 0.29 %)

3 g of this substance were dissolved in 10 ml of water and then mixed with 100 g of an approximately 30% aqueous solution of polyvinyl alcohol with a K value of 70 and a residual acetyl group content of about 12 % (Mowiol N 70-88), then with 5 ml of dibutyl phthalate and 10 g of finely divided silica are intensively mixed and colored with 0.2 g of crystal violet. A perlon fabric was double-coated on both sides with this screen printing varnish, dried, post-dried for 5 minutes at 100 ° C. and exposed for 2 minutes under a positive template with a 5000 watt xenon lamp at a distance of 65 cm. Development was then carried out with a cold water jet, the layer being removed from the mesh at the unexposed areas with a sharp edge. After drying, the stencil could be used with the

209809 / 087Ί

commercial, solvent-containing screen printing inks can be used for printing on paper and plastics.

The screen printing lacquer and the fabric pre-coated with it are at least unchanged in light sensitivity Can be stored for 10 weeks at room temperature.

Example 2

To dissolve 32.3 g of 3-methoxy-diphenylamine- * l-diazonium sulfate in 210 ml of 86% phosphoric acid, 33.3 g of finely powdered 1,3-bis-hydroxymethyl-4,6-diisopropyl- given benzene. After 12 1/2 hours of condensation at HO ⁰ C and ^ 1/2 days of standing at room temperature, the mixture was dissolved in 550 ml of water at 60 ° C and the methanesulfonate of the condensation product by adding 800 ml of aqueous solution, the 2 * 10 g sodium methanesulfonate contained, and cooled to room temperature deposited. For purification, the product was redissolved in water and precipitated again in the same way, finally separated off and dried. Yield: 50 g

209809/0871

With 100 g of a screen printing emulsion made from equal parts by weight of a 25% solution of polyvinyl alcohol with a K value of 75 and a residual acetyl group content of about 12 % (Mowiol N 75-88) and a dispersion of a vinyl acetate copolymer with 55 % pesticide content (Mowilith DM 2) existed, the aqueous solution of 2 g of the diazo compound prepared as just described was stirred. With this, a polyester screen printing fabric was coated, dried, exposed, developed with water and dried as usual. In order to make the image more visible, the developed stencil was colored by pouring an aqueous solution of crystal violet over it before drying. The excess dye not adsorbed on the layer parts was removed by rinsing before drying. The screen printing stencil is ideal for printing textiles with the usual aqueous textile printing inks.

Example 3

To dissolve 42.5 g of 2,5,4-triethoxy-dipheny1-4-diazonium sulfate (N 6.2 %) in 300 ml of 93% phosphoric acid, 25.9 g of ^, iP-bis- methoxymethyl

2041: 3S5

diphenyl ether dripped. After 3 hours of condensation at ^lM-1 IO ⁰ C, the mixture was diluted with 300 ml of water and the methanesulfonate by addition of 86o ml 26 deposited liger methanesulfonic acid, separated after repeated reprecipitation and dried.

Yield: 67.3 g (C 48.1 %, N 3.0 %, S 8.1 %, P 3.8 %)

A 30! Solution of polyvinyl alcohol, the 8-hour by stirring of polyvinyl alcohol having a K value of 50 and a residual acetyl group content of about 12% (N Mowiol 50-88) in water at about 85 ⁰ C in an open vessel was prepared, with 1 % polyglycol P 1200 (Dow Corning Corp.) was added as an antifoam agent, was mixed in a weight ratio of 3: 1 with the 55% dispersion of a vinyl acetate-maleate copolymer (Mowilith DM 1). 1 g of the water-soluble diazo compound described above was stirred into 250 g of the mixture.

With this screen printing varnish a screen was coated, dried, exposed, developed and the screen printing stencil produced in this way for printing on PVC *

Plastics used. She is free from shift defects, the so-called grease eyes, and therefore usable for long runs without masking work. If the stencil doesn't If more is needed, the fabric can be decoated, ζ-. "B. with chlorinated lime or sodium hypochlorite, preferred with lithium hypochlorite solution, cleaned and made reusable.

Example M

To a solution of 32.3 g of 3-methoxy-diphenylamine-4-diazonium sulfate in 100 ml of 86 % phosphoric acid, 25 μg of ¹ I, 4 -bis-methoxymethyldiphenyl ether were added dropwise with stirring. After 17 hours of condensation at 40 ° C., the methanesulfonate was deposited, cleaned and dried as described in the previous examples.

Yield: 53 g (C 55.3, N 6.5, S 6.2 % _t P 1.9, Cl <0.1, l Jt, H ₂ O 4.3 50

1000 g of a screen printing emulsion made from 3 parts of a 53 # vinyl acetate copolymer dispersion (Mowilith DM 2 HB) and 2 parts one by dissolving

2 0 9809/0871

and concentration was the 24 # solution of the polyvinyl alcohol used in Example 2, an aqueous solution of 15 g of the above-described diazo condensate and ¹ l g of Imperon blue KB (Farbwerke Hoechst) were added and stirred with it. A perforated nickel rotary cylinder with 576 mesh / cm (60 mesh) was coated 3 times with intermediate drying with this copying lacquer by moving a round rubber squeegee filled with it upwards on the outside of the standing perforated cylinder. The holes of the rotating cylinder were filled with light-sensitive lacquer. After rotary exposure with a mercury vapor tube lamp, the cylinder with the attached template rotating slowly, the layer at the unexposed areas was removed from the holes with a water shower. The round template, which was almost free of hairline cracks, was then slightly retouched and post-cured by tempering at 150-180 ° C and made ready for printing. With this printing form, large quantities of textiles could be printed. The printed nickel rotary stencil can be decoated with formic acid so that the perforated rotary cylinder can be used again.

209809/087 1

example 5

The condensation mixture of Example 4 was condensed for 5 hours at ¹ IO ⁰ C and the condensation product as described therein in the form of the salt of Chlormethansulf oic acid deposited.

With an aqueous solution of 4 g of this substance, 250 g of a 30% strength solution of the polyvinyl alcohol used in Example 1, which contained 5 % of finely divided polyvinyl acetate powder (Mowilith 30), were sensitized. As usual, a screen printing stencil was produced with it by coating, drying, exposure, developing, and drying.

Example 6

The procedure in Example 5 was used to produce the diazo condensate. However, the deposition took place in the form of the salt of propane-2-sulfonic acid.

A 10 35% aqueous solution of hydroxyethyl cellulose (Tylose HEC H 20p) was stirred with 1% of the photosensitive compound described above.

209809/0871

By coating a fine-meshed screen printing fabric on both sides 3 times, as well as exposing and developing a good stencil for solvent ink screen printing is made with water and drying.

Similar results were obtained when the diazo condensate was deposited as a salt of butane-1-sulfonic acid and otherwise processed in the same way became.

209809/0871

Claims (1)

Claims 1.) Photosensitive copying material for the production of screen printing forms, which contains a condensation product of an aromatic diazonium compound and a hydrophilic hardenable binder, characterized in that it contains a condensation product of at least one unit each of the general types ^A (~ ^D ) _n and B, which among each other by double bonded bridge members which are derived from a condensable carbonyl compound, in which A is the remainder of a compound containing at least two iso- or heterocyclic aromatic Contains rings and those in acidic medium in at least one place of the molecule with active carbonyl compound is condensable, D is a diazonium salt group which is attached to a aromatic carbon atom of A, 209809/0871 ORIGINAL INSPECTED η is an integer from 1 to IO and B is the remainder of a compound which is free of diazo groups and which in an acidic medium is at least is able to condense with an active carbonyl compound at one point in its molecule, wherein the anion of the diazonium salt is from an aliphatic Monosulfonic acid with 1 to 6 carbon atoms is derived. 2. Composition according to claim 1, characterized in that the condensation product is used as the salt Methanesulfonic acid is present. 3. Composition according to claim 1, characterized in that the condensation product is a condensate from a 3-alkoxy-diphenylamine-4-diazonium salt and one Diphenyl ether, diphenyl sulfide, diphenyl methane or diphenyl derivative is. ¹ I. mass according to claim 1 or 3, characterized characterized in that the condensation product contains the units A (-D) _n and B in a molar ratio of 1: 0.5 to 1: 2. 209809/0871 5. Composition according to claim 1, characterized in that it contains the condensation product in a proportion of 2 to 20 % of their Peststoffgeha.lts. 6. Composition according to claim 1, characterized in that it is in the form of an aqueous solution, 7. Composition according to claim 6, characterized in that the solution also has a dispersed Contains filler. 8. Composition according to claim 7 »characterized in that the dispersed filler is a water-insoluble is an organic polymer. 9. Composition according to claim 6, characterized in that the hydrophilic binder is polyvinyl alcohol is. 10. Composition according to claims 8 and 9, characterized in that the water-insoluble organic polymer is a vinyl acetate polymer. 209809/0871 11. Composition according to claim 1, characterized in that it is a solid photosensitive layer is present on a screen printing support. 209809/0871